Jana Narayan Ch, Jagodič Marko, Brandão Paula, Patra Moumita, Herchel Radovan, Jagličić Zvonko, Panja Anangamohan
Department of Chemistry, Panskura Banamali College Panskura RS WB 721152 India
Institute of Mathematics, Physics and Mechanics Jadranska 19 1000 Ljubljana Slovenia.
RSC Adv. 2023 Apr 11;13(17):11311-11323. doi: 10.1039/d3ra00737e.
Two new doubly -N bridged (1 and 3) and six new doubly -NCO bridged Ni complexes (2, 4-8) with six different NO donor Schiff base ligands have been synthesized and magneto-structurally characterized. All these neutral complex molecules are isostructural and constitute edge sharing bioctahedral structures. Magnetic studies revealed that all these complexes exhibit ferromagnetic interaction through bridging pseudohalides with ferromagnetic coupling constant being significantly higher for azide-bridged complexes than that of the cyanate analogues. This is consistent with the literature reported data and also the presence of polarizable π systems and two different N and O donor atoms in cyanate ion, rendering it a poor magnetic coupler in comparison to azide analogues. Although, the magneto-structurally characterized doubly -N bridged Ni complexes are abundant, only few such complexes with -bridging NCO ions are reported in the literature. Remarkably, addition of these six new examples in this ever-growing series of doubly -NCO bridged systems gives us an opportunity to analyse the precise magneto-structural correlation in this system, showing a general trend in which the value increases with an increase in bridging angles. Therefore, the high degree of structural and magnetic resemblances by inclusion of six new examples in this series is the major achievement of the present work. An elaborate DFT study was performed resulting in magneto-structural correlation showing that nature and value of the -parameter is defined not only by Ni-N-Ni bond angles, but an important role is also played by the Ni1-Ni2-N-X dihedral angle (N and X are bridging N and terminal N or O atom of bridging ligands, respectively).
已合成了两种新的双 -N 桥联（1 和 3）以及六种新的双 -NCO 桥联镍配合物（2、4 - 8），它们带有六种不同的含 NO 供体的席夫碱配体，并进行了磁结构表征。所有这些中性配合物分子都是同构的，构成了边共享双八面体结构。磁性研究表明，所有这些配合物通过桥联拟卤化物表现出铁磁相互作用，叠氮桥联配合物的铁磁耦合常数明显高于氰酸酯类似物。这与文献报道的数据一致，并且氰酸根离子中存在可极化的 π 体系以及两个不同的 N 和 O 供体原子，使其与叠氮类似物相比成为较差的磁耦合体。尽管，经磁结构表征的双 -N 桥联镍配合物很多，但文献中仅报道了少数此类含 -桥联 NCO 离子的配合物。值得注意的是，在这个不断增长的双 -NCO 桥联体系系列中增加这六个新例子，使我们有机会分析该体系中精确的磁结构相关性，显示出随着桥联角度增加， 值增大的一般趋势。因此，在该系列中纳入六个新例子所呈现的高度结构和磁性相似性是本工作的主要成果。进行了详细的密度泛函理论（DFT）研究，得出磁结构相关性，表明 -参数的性质和值不仅由 Ni - N - Ni 键角定义，而且 Ni1 - Ni2 - N - X 二面角（N 和 X 分别是桥联配体的桥联 N 和末端 N 或 O 原子）也起重要作用。
